The invention relates to a device for raising an edge of a single sheet situated topmost on a pile of sheets.
Specifically, but not exclusively, it is useful for raising resin-impregnated paper sheets arranged in a pile one on top of another. This operation is performed, for example, in the manufacture of phenolic-melaminic decorative plastic laminated sheets, or in the field of treated post-formable or pre-formable panels. Both of the aforementioned operations involve feeding of paper from a roll into an impregnating machine; after which the paper is cut into sheets, which are then piled one on top of another to form piles.
The device of the present invention raises said sheets one-by-one from the pile, so that the sheets can be sent on to subsequent work operations. This raising operation is at present carried out by hand by one or more operatives. Even when done by hand the separating of the sheets is problematic. The tendency of resinated sheets is to stick together, forming an undesirable compacted block, which obviously increases in stickiness and compactability with the quantity of resin used in the operation and therefore absorbed by the paper. The weight of the pile also increases with the degree of resination of the paper: a typical pile can be formed by 1500 to 2000 sheets, and can weigh up to 2000 Kg. If a pile is left undisturbed for a considerable time, the compactness of the pile becomes even more of a problem as the resin dries.
A further drawback in the prior art is the amount of labour time required and the subsequent slowness of the laminate or panel formation.
In the field of treated panels the prior art teaches a device equipped with suckers to raise the sheet situated on top of the pile. It is still necessary, however, for an operative to detach the topmost sheet from the underlying one before replacing it in the same position at the top of the pile; only then can the sheet can be raised by the suckers.